Hopper door actuating mechanism

ABSTRACT

This invention relates to a vehicle discharge arrangement for hoppers which may be carried by a railway car or other type of vehicle. Bottom doors are pivoted about a generally horizontal axis to open lowered and closed raised positions and are provided at their lower ends with edge portions positioned in overlapping closed positions. One door is operated by a transversely extending arm which in turn is moved by means of a vertical lever pivoted on a supporting sill extending longitudinally of the vehicle. The other door is interconnected to move with the first door by means of a linkage and bellcrank mechanism which permits the first door to move initially out of the closed position before any substantial movement of the second door occurs. In a partially opened position the overlapping edge portion of the first door is out of the way of the second door which then can pivot to its open position. The linkage and bellcrank mechanism, as well as the transverse arm and vertical lever means, are arranged to be positioned in overcenter locking configurations to positively secure the doors in their closed positions.

United States Patent [72] Inventors Herman A. Aquino Hobart; Ernest J.Nagy, Munster; William R. Shaver, Mumer, all of, Ind. [21 Appl. No.777,430 [22] Filed Nov. 20, 1968 (45] Patented Aug. 3, 1971 [73]Assignee Pullman incorporated Chicago, Ill.

[54] HOPPER DOOR ACTUA'I'ING MECHANISM 22 Claims, 7 Drawing Fig.

Primary Examiner-Arthur L. La Point Assistant Examiner-Howard BeltranAttorneys-J-lilmond O. Vogel and Wayne Morris Russell ABSTRACT: Thisinvention relates to a vehicle discharge arrangement for hoppers whichmay be carried by a railway car or other type of vehicle. Bottom doorsare pivoted about a generally horizontal axis to open lowered and closedraised positions and are provided at their lower ends with edge portionspositioned in overlapping closed positions. One door is operated by atransversely extending arm which in turn is moved by means of a verticallever pivoted on a supporting sill extending longitudinally of thevehicle. The other door is interconnected to move with the first door bymeans of a linkage and bellcrank mechanism which permits the first doorto move initially out of the closed position before any substantialmovement of the second door occurs. In a partially opened position theoverlapping edge portion of the first door is out of the way of thesecond door which then can pivot to its open position. The linkage andbellcrank mechanism, as well as the transverse arm and vertical levermeans, are arranged to be positioned in overcenter lockingconfigurations to positively secure the doors in their closed positions.

PATENTEU AUG 3 I97! SHEET 1 BF 4 0 WWM X m AV N W Jmw W MM MR y RELPATENIEnms 3:911 3,596, 0

sum 2 or 4 INVENTORS HERMAN A. AOUINO ERNESTJ. NAGY WILLIAM R. SHAVER BY40. 0M

M ATT'Y.

PATENTED AUG 3 l9?! SHEET 3 OF 4 INVENTORS HERMAN A.AOUINO ERNEST J.NAGY WILLIAM R. SHAVER ATT Y.

PATENTED M18 3 I971 SHEET '4 BF 4 IN VENTORS HERMAN A. AQUINO ERNEST J.NAGY WILLIAM R. SHAVER M (9/ ATTY.

HOPPERIJOOR ACTUA'IING MECHANISM SUMMARY The primary object of theinvention is to provide an improved door opening mechanism for bottomdischarge of a hopper which permits quick positive opening and closingof the doors with an improved door actuating mechanism and doorconfiguration. In the closed position overlapping edge portions of thedoors provide an effective closure and are securely retained againstopening by overcenter linkage and DESCRIPTION OF THE DRAWINGS FIG. 1 isa side elevational view of a railway hopper car;

FIG. 2 is an enlarged sectional view of a door-operating mechanism takensubstantially along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view taken substantially along the line 3-3of FIG. 1;

FIG. 4 is a side elevational view, partially in section, taken along theline 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. 3;

FIG. 6 is a perspective view of a portion of a hopper car showing adoor-operating mechanism; and

FIG. 7 is a cross-sectional view taken substantially along the line 7-7of FIG. 2.

DETAILED DESCRIPTION FIG. 1 discloses a railway hopper car 10, supportedon a wheeled underframe 11 which includes a longitudinally extendingcenter sill 12 formed of channel members 13 connected at their upperends by top plates 14 and bottom plates 15 extending longitudinallyalong said center sill. Theplates l4 and 15 are spaced to provide fouropenings 16 aloiig said center sill 12, one of said openings 16 beingbest shown in FIGS. 2, 3, and 6. As best shown in FIG. 1, the hopper car10 is provided with conventional vertical side walls 17. In thedisclosure shown in FIG. 1 the hopper car 10 includes hopper structuresdesignated generally at 18. A pair of these identical hopper structures18 are provided on each side of the center sill 12, the said hopperstructures 18 as best shown in FIG. 1 being in longitudinally spaced andaligned relation. Each hopper structure 18 includes end slope sheets 19and 20 with a partition wall 21, as shown in FIG. 1, separating eachpair of hopper structures 18. EAch hopper structure 18 also includes, asbest shown in FIG. 3, an inner slope sheet 22 adjacent the center sill12. The hopper structures 18 are supported on the wheeled underframe 11in a suitable manner not disclosed in detail.

A pair of door-actuating mechanisms 23 are supported on the center sill12 in longitudinally spaced relation. Each actuating mechanism 23comprises two vertical levers 24 which are pivotally connected asindicated at 25 to angle brackets 26 suitably supported on the centersill 12. The vertical levers 24 extend through the openings 16 in thecenter sill l2 and project downwardly with respect thereto. Guide angles27 suitably connected to the center sill I2 guide the lower ends of thelevers 24, as best shown in FIG. 3. Longitudinally extending actuatingmeans 28 are pivotally connected'as indicated at 29 to the levers 24 andin tum are connected to piston assemblies 28', as shown in FIG. 1, ofpneumatic cylinders 29 supported at opposite ends of the car 10 as bestshown in FIG. 1. Pneumatic cylinders 29 may be suitably connected to asource of pressure for moving the beams 28 in a longitudinal direction,thereby actuating pivotal movement of the levers 24 which actuate dooroperating mechanisms 52 at respectively opposite sides of center sill 12to open or close pairs of doors 38 and 39 at each side of the centersill.

The lower ends of the levers 24 are provided with pivot brackets 30disposed on opposite sides of said levers 24. Each pivot bracket 30includes a socket 31 in which a ball 32 is swiveled. Each ball 32 issuitably connected to an arm 33 as best shown in FIG. 3, extendinglaterally outwardly in opposite directions with respect to the centersill 12. A ball 34 is connected to the other end of each arm 33 and issuitably swiveled in a socket 35 provided in pivot brackets 36. Thepivot brackets 36 are secured to a pair of connecting structures 37which in turn are suitably connected to the bottom side of each bottomdoor generally designated at 38. Each hopper structure 18 is providedwith a bottom master door 38 and a bottom slave door each of which isvertically pivotal with respect to an opening 40 designated in FIG. 3,at the lower end of each hopper structure 18. The doors 38 and 39 areprovided with hinge elements 41 hingedly connected by means of hingepins 42 to brackets 43. The brackets 43 for the door 38 are suitablyconnected to the center sill structure 12 and the brackets 43 for thedoor 39 are suitably connected to a horizontally extending anglestructure 44 suitably connected to the outer surface of the side walls17 as best shown in FIG. 3. The doors 38 and 39 also include upwardlyextending end flanges 45 and the end slope sheets 19 adjacent theopening 40 are provided with outwardly projecting flanges 46.

As best shown in FIG. 3, the doors 38 and 39 are disposed in relativeV-shaped relation and include inner converging bottom sheets 47 and 48which as best shown in FIG. 7 are provided at their lower edges withhorizontal flanges 49 and 50 respectively on said bottom sheets 47 and48. The flat horizontal edge portions 49 and 50 are in the closedposition of the doors 38 and 39 in overlapping relation as indicated. Alongitudinally extending reinforcing member 51 is connected to the flatportion 49 and to the outer surface of the door 38 as indicated in FIG.7.

The hopper structure 18 at each side of the center sill 12 includes atopposite ends thereof a pair of linkage and bellcrank mechanismsgenerally designated at 52. Each such actuating mechanism 52 for thehopper structure 18 at respectively opposite sides of the center sill isactuated by means of the dooractuating mechanisms 23. Each mechanism 52,as best shown in FIGS. 3 and 6, actuates a pair of doors and comprises afirst link 53 which is pivotally connected as indicated at 54 to a pivotbracket 55 suitably attached to the door 38. The first link 53 includesat its upper end a curved end portion 56 which in turn is pivotallyconnected, as indicated at 57, to a bellcrank 58. The bellcrank 58Includes a pivot fulcrum 59 including a spacer 60 supported on the outerside of each of the end slope sheets 19. A second link 61 is pivotallyconnected at 62 to another end of the bellcrank 58. A pivotal connection63 pivotally connects the link 61 to a pivot bracket 64 each beingdisposed on opposite ends of the door 39.

THE OPERATION In the closed position of the doors 38 and 39, as bestshown in FIGS. 1, 2 and 3, the door-actuating mechanisms 23 are disposedin a locked overcenter position. The piston assemblies 28' are at theouter ends of the cylinder 29 and the actuating beams 28 have pivotedthe vertical levers 24 so that the ms 33 are positioned transversely andslightly in an overposition relative to a vertical plane extendingtransversely through the ball connections 32-34 which are secured to thebottom of the door 38. Thus in this position the doors 38 and 39 arefirmly locked by the overcenter positioning of the arms 33. As bestshown in FIG. 3, a centerline A though the pivotal connections 62 andpivot pins 63 is disposed overcenter with respect to the center of thepivot fulcrum 59 so that the said link 61 is also in an overcenterposition which securely locks the bellcrank 58 and link 53 in the closedposition further assuring that the gates 38 and 39 are positivelyclosed.

It should be noted that when the links 61 at the opposite ends of door39 are disposed in the overcenter position, the product of the forceoccurring in the links acting on a line extending through the endpivotal connections 62 and 63 and the perpendicular distance from thisline to the center of the bellcrank fulcrum pivot 59, is greater thanthe product of the force occurring in links 53 acting on a lineextending through the end pivotal connections 57 and 54 and theperpendicular distance from this latter line to the center of the pivot.The force in the links 61 created by the weight of the door 39 or thisweight combined with the weight of the lading thereon. The force inlinks 53 is created by the weight of the door 38 or this weight combinedwith that of the lading thereon. Thus under the force conditionsdescribed the doors will tend to remain closed and when such forceconditions are reversed the doors will open.

As shown in FIG. 7, the horizontal flat edge 50 is in overlapping andseating relation on the flange 49 of the door 38 and thus with theovercenter action of the arms 33 and the links 61 a positive lockingmeans for the doors 38 and 39 is provided. This of course is extremelydesirable in view of the heavy loads which the hopper must carry.

In the discharge operation of material from the hopper structures 18, itof course is desired that a rapid discharge is effected so that thedoors 38 and 39 must open quickly. The discharge operation is asfollows:

The pneumatic cylinders 29 are charged with air to cause the pistonassemblies 28 to move the beams 28 in a direction longitudinallyinwardly from the ends of the car which in turn causes the levers 24 topivot. The pivotal action of the levers 24 moves the arms 33 as shown inFIG. 2 in a substantially clockwise direction which in turn causesmovement of all of the doors 38 downwardly about their pivotalconnections. As each door 38 moves downwardly the link 53 of eachmechanism 52 causes swinging movement of the bellcrank 58 about thepivot fulcrum 59. This also of course causes the upper end of the link61 to move from the overcenter position shown in FIG. 3 wherein thecenterline A moves beyond the pivot fulcrum center. During this movementto the position of the line designated at B there is only a slightdownward movement of the associated door 39. On the other hand, the door38 has during this movement moved to the dotted line position shown inFIG. 3 wherein the flat edge 49 is disposed out of the way of the pathof movement of the flat edge 50 of the door 39. Thus there is a timeddelay or time sequence provided by the links 53 and 61 and bellcrank 58which act as a guide means for the links so that the doors 39 do notopen until the doors 38 are each in an out-of-the-way position. Thus thepositioning of the links 53 and 61 is critical to provide a sequentialor timed operation of the doors 38 and 39. As indicated, the bellcrank58 in each mechanism acts as a guide for the links so that such sequenceis effective. Due to the heavy weight of the material in each hopperstructure 18 at each side of the center sill l2 movement of the doors 38and 39 is of course very rapid and such sequence of operation occurs ina fraction of time. It is of course understood that each door 39operates completely in response to the movement of the associated door38 as determined by the linkage and bellcrank mechanism and that thepairs of doors on opposite sides of the center sill are actuatedsimultaneously by the mechanisms 23 operatively connected with the doors38. The bellcranks 58 guide the movement of the linkages 53 and 61 sothat the movement of the gate 39 is retarded or delayed until the gate38 has moved to an out-of-the-way position toward full opening.

The structure disclosed and described thus permits the quick opening ofthe doors 38 and 39 and the effective locking and positioning of thedoors in their closed position. In the closed position the doors areeffectively sealed by means of their overlapping engagement of the flatedges 49 and 50 and the door 38 which is effectively supported by thearms 33 on the center sill, in turn also effectively assist insupporting of the weight on the doors 39. An efi'ective and simplifiedstructure is thus achieved which meets the objectives of the invention.

What I claim is:

l. A vehicle bottom discharge arrangement for discharging a load from avehicle having a hopper, comprising:

first and second doors pivotally connected to said vehicle, below saidhopper for vertical swinging movement from closed to open positions,

said doors having adjacent edge portions in closing overlappingengagement in the closed position wherein said first door overlaps saidsecond door door-operating mechanism including force-transmitting meansconnected to said first door for transmitting a force applied exteriorlyof said hopper to move said first door between said positions,

second force-transmitting means pivotally connected between said doors,said second force-transmitting means being responsive to said movementof said first door to swing said second door to open and closedpositions, and

means guiding movement of said second force-transmitting means duringmovement of said first door to provide for sequential movement of thesecond door with respect to the first door to retard movement of saidsecond door until said edge portion of said first door is disposed outof the path of movement of said edge portion of said second door.

2. The invention in accordance with claim 1,

said doors in the closed position being positioned in V- shaped relationand converging downwardly from said hopper.

3. The invention in accordance with claim 2,

said edge portions of said doors extending substantially horizontallyand being disposed in relative overlapping relation at the convergenceof said doors.

4. The invention in accordance with claim 2,

said second force transmitting means comprising a first link pivotallyconnected to said first door,

a second link pivotally connected to said second door,

said guide means being pivotally interconnected between said links, and

means movably connecting said guide means to said vehicle.

5. The invention in' accordance with claim 1,

said second force transmitting means comprising a first link pivotallyconnected to said first door, I

a second link pivotally connected to said second door,

said guide means being pivotally interconnected between said links, and

means movably connecting said guide means to said vehicle.

6. The invention in accordance with claim 5,

said guide means including a bellcrank having at one end a fulcrumpivotally connected to said vehicle, and

means respectively pivotally connecting said links to the other ends ofsaid bellcrank.

7. A vehicle bottom discharge arrangement for discharging a load from avehicle having a hopper: comprising:

first and second doors pivotally connected to said vehicle for verticalswinging movement from closed to open positions,

door-operating mechanism including a horizontal movable arm having oneend connected to said first door for moving the same between saidpositions,

a first link pivotally connected to said first door,

a second link pivotally connected to said second door, and

guide means pivotally mounted on said vehicle and pivotally connected tosaid links whereby said second door is moved sequentially relative tosaid first door between said positions in response to movement of saidfirst door,

said doors having edge portions in the closed position being positionedin overlapping relation wherein said first door overlaps said seconddoor, and

said first door being initially moved out of the path of movement ofsaid second door whereby said second door is free to move to its openposition.

8. The invention in accordance with claim 7,

said guide means comprising a bellcrank.

9. The invention in accordance with claim 8,

said bellcrank having its fulcrum supported on said vehicle,

said second link extending vertically and being pivotally connected toan end of said bellcrank disposed above said fulcrum,

said first link extending above said fulcrum and having an end pivotallyconnected to an end of said bellcrank disposed laterally to one side ofsaid fulcrum, whereby during movement of said first door to an openposition the movement of said second door is retarded until said firstdoor is partially opened.

10. The invention in accordance with claim 7,

said guide means including a bellcrank having its fulcrum supported onsaid vehicle,

said second link extending vertically and being pivotally connected toan end of said bellcrank disposed above said fulcrum,

said first link extending above said fulcrum and having an end pivotallyconnected to an end of said bellcrank disposed laterally to one side ofsaid fulcrum, whereby during movement of said first door to an openposition the movement of said second door is retarded until said firstdoor is partially opened.

11. The invention in accordance with claim 10,

said doors having edge portions in the closed position being positionedin overlapping relation, and

said first door being initially moved out of the path of movement ofsaid second door whereby said second door is free to move to its openposition.

12. The invention in accordance with claim 10,

said second link in the closed position having a vertical centerlinethrough the pivotal connections of said second link to said second doorand to said guide means and bellcrank being disposed to one side of saidfulcrum in an overcenter position.

13. The invention in accordance with claim 7,

said second link in the closed position having a vertical centerlinethrough the pivotal connections of said second link to said second doorand to said guide means and bellcrank having a fulcrum on the vehicleand being disposed to one side of said fulcrum in an overcenterposition.

14. The invention in accordance with claim 13,

said other end of said first arm being movable with said vertical arm toan overcenter position in the closed position of said doors.

15. The invention in accordance with claim 7,

said vehicle including a longitudinally extending support disposedlaterally with respect to said doors,

a vertical arm pivotally connected to said support,

means for pivotally moving said vertical arm,

means pivotally connecting the other end of said first mentioned arm tosaid vertical arm whereby during longitudinal movement of said verticalarm said other end of said first arm is moved longitudinally to exert atransverse force for moving said doors.

16. The invention in accordance with claim 15,

said other end of said first arm being movable with said vertical arm toan overcenter position in the closed position of said doors.

17. The invention in accordance with claim 7,

said doors being disposed in V-shaped relation having inner surfacesconverging downwardly relative to said hopper and having saidoverlapping edge portions extending horizontally with the edge portionof said first door being disposed below the edge portion of said seconddoor.

18. The invention in accordance with claim 7,

said vehicle including a longitudinally extending support disposedlaterally with respect to said doors,

a vertical arm pivotally connected to said support,

means for pivotally moving said vertical arm,

means pivotally connecting the other end of said horizontal movable armto said vertical arm whereby during longitudinal movement of saidvertical arm said other end of said horizontal movable arm is movedlongitudinally to exert a transverse force for moving said doors.

19. A vehicle bottom discharge arrangement for discharging a load from avehicle having a hopper, comprising:

first and second doors extendinglongitudinally of the vehicle andpivotally connected to said vehicle, below said for transmitting a forceappliedexteriorly of said hopper to move said doors between saidpositions, said forcetransmitting means extending substantially thelength of the hopper for transmitting drive to the doors along thelengths of the doors for uniformly opening them from a locked positionto an open position,

second force-transmitting means pivotally connected between said doors,

said second force-transmitting means being responsive to said movementof said first door to swing said second door to open and closedpositions, and

said second force transmitting means having means for guiding movementof said second force transmitting means during movement of said one doorto retard movement of said other door moving sequentially relative tosaid first door until said edge portion of said one door is disposed outof the path of movement of said edge portion-of said other door.

20. A vehicle bottomdischarge arrangement for discharging a load fromthe hopper of a vehicle, comprising:

a pair of interconnected master and slave doors extending longitudinallyof the vehicle and pivotally connected to said vehicle for swingingmovement from a door closed and locked position to a door open andunlocked position,

said doors having adjacent longitudinally extending lateral edgeportions in closing overlapping load-supporting interengagement with oneanother in the door closed position, the edge portion of the master dooroverlapping in load-supporting relation underneath the edge portion ofthe slave door preventing opening movement of the slave door from thelocked position,

dooroperating mechanism including movable arm means including a pair oflongitudinally spaced lateral extending door arms each having one endconnected to said master door for moving the same between said positionsand preventing opening of the master door and thereby the slave door inthe locked position, said door-operating mechanism further havinglongitudinally extending forcetransmitting means extending substantiallythe length of the hopper and connecting with the door arms fortransmitting drive to the doors along the lengths of the doorsfor-uniformly opening then from the locked closed position to theunlocked open position,

first link means including a pair of longitudinally spaced laterallyextending links each being connected with said master door and with arespective door arm, and extending upwardly from the master door,

second link means including a pair of longitudinally spaced laterallyextending links each being pivotally connected to said slave door andextending upwardly therefrom, and

each link meansbeing so pivotally interconnected with one another abovethe doors with said master door being first moved by said arm means toretard and subsequently move said slave door between said positions.

21. A vehicle bottom discharge arrangement for discharging a load fromthe hopper of a vehicle comprising:

a pair of interconnecting master and slave doors extendinglongitudinally of the vehicle and pivotally connected to door-operatingmechanism including laterally extending movable arm means andlongitudinally extending forcetransmitting means extending substantiallythe lengthof the hopper and connecting with the arm means fortransmitting drive to the master door, said longitudinally extendingforce transmitting means connecting with said arm means in an overcenterlocked position in the closed position of the doors attendant to holdingthe doors in the closed and locked position,

first link means being connected with said master door,

second link means being connected with said slave door and pivotallyconnecting with said first link means,

said master door being moved first by said arm means to retard andsubsequently move said slave door between said locked and unlockedpositions.

22. The invention according to claim 21, and

said force-transmitting means having means for providing an overcenterlocking of the door operating mechanism attendant to keeping the masterdoor in load-supporting relation against the slave door.

1. A vehicle bottom discharge arrangement for discharging a load from avehicle having a hopper, comprising: first and second doors pivotallyconnected to said vehicle, below said hopper for vertical swingingmovement from closed to open positions, said doors having adjacent edgeportions in closing overlapping engagement in the closed positionwherein said first door overlaps said second door door-operatingmechanism including force-transmitting means connected to said firstdoor for transmitting a force applied exteriorly of said hopper to movesaid first door between said positions, second force-transmitting meanspivotally connected between said doors, said second force-transmittingmeans being responsive to said movement of said first door to swing saidsecond door to open and closed positions, and means guiding movement ofsaid second force-transmitting means during movement of said first doorto provide for sequential movement of the second door with respect tothe first door to retard movement of said second door until said edgeportion of said first door is disposed out of the path of movement ofsaid edge portion of said second door.
 2. The invention in accordancewith claim 1, said doors in the closed position being positioned inV-shaped relation and converging downwardly from said hopper.
 3. THeinvention in accordance with claim 2, said edge portions of said doorsextending substantially horizontally and being disposed in relativeoverlapping relation at the convergence of said doors.
 4. The inventionin accordance with claim 2, said second force transmitting meanscomprising a first link pivotally connected to said first door, a secondlink pivotally connected to said second door, said guide means beingpivotally interconnected between said links, and means movablyconnecting said guide means to said vehicle.
 5. The invention inaccordance with claim 1, said second force transmitting means comprisinga first link pivotally connected to said first door, a second linkpivotally connected to said second door, said guide means beingpivotally interconnected between said links, and means movablyconnecting said guide means to said vehicle.
 6. The invention inaccordance with claim 5, said guide means including a bellcrank havingat one end a fulcrum pivotally connected to said vehicle, and meansrespectively pivotally connecting said links to the other ends of saidbellcrank.
 7. A vehicle bottom discharge arrangement for discharging aload from a vehicle having a hopper: comprising: first and second doorspivotally connected to said vehicle for vertical swinging movement fromclosed to open positions, door-operating mechanism including ahorizontal movable arm having one end connected to said first door formoving the same between said positions, a first link pivotally connectedto said first door, a second link pivotally connected to said seconddoor, and guide means pivotally mounted on said vehicle and pivotallyconnected to said links whereby said second door is moved sequentiallyrelative to said first door between said positions in response tomovement of said first door, said doors having edge portions in theclosed position being positioned in overlapping relation wherein saidfirst door overlaps said second door, and said first door beinginitially moved out of the path of movement of said second door wherebysaid second door is free to move to its open position.
 8. The inventionin accordance with claim 7, said guide means comprising a bellcrank. 9.The invention in accordance with claim 8, said bellcrank having itsfulcrum supported on said vehicle, said second link extending verticallyand being pivotally connected to an end of said bellcrank disposed abovesaid fulcrum, said first link extending above said fulcrum and having anend pivotally connected to an end of said bellcrank disposed laterallyto one side of said fulcrum, whereby during movement of said first doorto an open position the movement of said second door is retarded untilsaid first door is partially opened.
 10. The invention in accordancewith claim 7, said guide means including a bellcrank having its fulcrumsupported on said vehicle, said second link extending vertically andbeing pivotally connected to an end of said bellcrank disposed abovesaid fulcrum, said first link extending above said fulcrum and having anend pivotally connected to an end of said bellcrank disposed laterallyto one side of said fulcrum, whereby during movement of said first doorto an open position the movement of said second door is retarded untilsaid first door is partially opened.
 11. The invention in accordancewith claim 10, said doors having edge portions in the closed positionbeing positioned in overlapping relation, and said first door beinginitially moved out of the path of movement of said second door wherebysaid second door is free to move to its open position.
 12. The inventionin accordance with claim 10, said second link in the closed positionhaving a vertical centerline through the pivotal connections of saidsecond link to said second door and to said guide means and bellcrankbeing disposed to one side of said fulcruM in an overcenter position.13. The invention in accordance with claim 7, said second link in theclosed position having a vertical centerline through the pivotalconnections of said second link to said second door and to said guidemeans and bellcrank having a fulcrum on the vehicle and being disposedto one side of said fulcrum in an overcenter position.
 14. The inventionin accordance with claim 13, said other end of said first arm beingmovable with said vertical arm to an overcenter position in the closedposition of said doors.
 15. The invention in accordance with claim 7,said vehicle including a longitudinally extending support disposedlaterally with respect to said doors, a vertical arm pivotally connectedto said support, means for pivotally moving said vertical arm, meanspivotally connecting the other end of said first mentioned arm to saidvertical arm whereby during longitudinal movement of said vertical armsaid other end of said first arm is moved longitudinally to exert atransverse force for moving said doors.
 16. The invention in accordancewith claim 15, said other end of said first arm being movable with saidvertical arm to an overcenter position in the closed position of saiddoors.
 17. The invention in accordance with claim 7, said doors beingdisposed in V-shaped relation having inner surfaces convergingdownwardly relative to said hopper and having said overlapping edgeportions extending horizontally with the edge portion of said first doorbeing disposed below the edge portion of said second door.
 18. Theinvention in accordance with claim 7, said vehicle including alongitudinally extending support disposed laterally with respect to saiddoors, a vertical arm pivotally connected to said support, means forpivotally moving said vertical arm, means pivotally connecting the otherend of said horizontal movable arm to said vertical arm whereby duringlongitudinal movement of said vertical arm said other end of saidhorizontal movable arm is moved longitudinally to exert a transverseforce for moving said doors.
 19. A vehicle bottom discharge arrangementfor discharging a load from a vehicle having a hopper, comprising: firstand second doors extending longitudinally of the vehicle and pivotallyconnected to said vehicle, below said hopper for swinging movement fromclosed to open positions, said doors having adjacent longitudinallyextending lateral edge portions in closing overlapping load supportinginterengagement in the closed position, the edge portion of one dooroverlapping the edge portion of the other door preventing openingmovement of the other door with respect to the one door, door-operatingmechanism including longitudinally extending force transmitting meansconnected to said one door for transmitting a force applied exteriorlyof said hopper to move said doors between said positions, saidforce-transmitting means extending substantially the length of thehopper for transmitting drive to the doors along the lengths of thedoors for uniformly opening them from a locked position to an openposition, second force-transmitting means pivotally connected betweensaid doors, said second force-transmitting means being responsive tosaid movement of said first door to swing said second door to open andclosed positions, and said second force transmitting means having meansfor guiding movement of said second force transmitting means duringmovement of said one door to retard movement of said other door movingsequentially relative to said first door until said edge portion of saidone door is disposed out of the path of movement of said edge portion ofsaid other door.
 20. A vehicle bottom discharge arrangement fordischarging a load from the hopper of a vehicle, comprising: a pair ofinterconnected master and slave doors extending longitudinally of thevehicle and pivotally connected to said vehicle for swingIng movementfrom a door closed and locked position to a door open and unlockedposition, said doors having adjacent longitudinally extending lateraledge portions in closing overlapping load-supporting interengagementwith one another in the door closed position, the edge portion of themaster door overlapping in load-supporting relation underneath the edgeportion of the slave door preventing opening movement of the slave doorfrom the locked position, door-operating mechanism including movable armmeans including a pair of longitudinally spaced lateral extending doorarms each having one end connected to said master door for moving thesame between said positions and preventing opening of the master doorand thereby the slave door in the locked position, said door-operatingmechanism further having longitudinally extending force-transmittingmeans extending substantially the length of the hopper and connectingwith the door arms for transmitting drive to the doors along the lengthsof the doors for uniformly opening then from the locked closed positionto the unlocked open position, first link means including a pair oflongitudinally spaced laterally extending links each being connectedwith said master door and with a respective door arm, and extendingupwardly from the master door, second link means including a pair oflongitudinally spaced laterally extending links each being pivotallyconnected to said slave door and extending upwardly therefrom, and eachlink means being so pivotally interconnected with one another above thedoors with said master door being first moved by said arm means toretard and subsequently move said slave door between said positions. 21.A vehicle bottom discharge arrangement for discharging a load from thehopper of a vehicle comprising: a pair of interconnecting master andslave doors extending longitudinally of the vehicle and pivotallyconnected to the vehicle for swinging movement from a door closed andlocked position to a door open and unlocked position, said doors havingadjacent longitudinally extending lateral edge portions in closedoverlapping engagement with one another in the door-closed position, theedge portion of the master door overlapping in load-supporting relationwith the edge portion of the slave door preventing opening of the slavedoor from the locked position, door-operating mechanism includinglaterally extending movable arm means and longitudinally extending forcetransmitting means extending substantially the length of the hopper andconnecting with the arm means for transmitting drive to the master door,said longitudinally extending force transmitting means connecting withsaid arm means in an overcenter locked position in the closed positionof the doors attendant to holding the doors in the closed and lockedposition, first link means being connected with said master door, secondlink means being connected with said slave door and pivotally connectingwith said first link means, said master door being moved first by saidarm means to retard and subsequently move said slave door between saidlocked and unlocked positions.
 22. The invention according to claim 21,and said force-transmitting means having means for providing anovercenter locking of the door operating mechanism attendant to keepingthe master door in load-supporting relation against the slave door.